Magnetic circuit and method of forming same



July 28,-1942. H E WHEELER 2,291,013

MAGNETIC CIRCUIT AND METHOD OF FORMING SAME INVENTOR. Hmm mw M/m e ATTORNEY July 2s, 1942.

H. E. WHEELER .MAGNETIC CIRCUIT AND METHOD OF FORMING SAME 2 Sheets-Sheefl 2 Filed Jan. 30, 1940 IN VENTOR. Ham. @No h/mseme @www ATTORNEYS Patented .July 28, l1942 MAGNETIC cmcm'r AND ME'rnonor FonMlNG SAME nai-ionen. wheeler, Elyria, omo, miglior to 'rho l General Industries Company, Elyria., Ohio, a

corporation oi' Ohio Appuosuon January 30(1940, senor No. 316,395 v (o1. 1115-21) 2 Claims.

This invention relates to magnetic circuits and a method ofiorming such circuits, and more par-l ticularly to an improved construction for magnetizable cores of the type used in motors; relays, transformers and other electrical devices.

An object of my invention is to provide an improved construction and method for producing magnet cores in which the core is made in sections` so asv to facilitate the assembly of the magnet coil or otherparts of the device and in which these sections are so formed that they can beI readily connectedwith each other with minimum magnetic-reluctance at the point of connection.

Another "object'of my` invention isto provide animproved. method and construction for producing magnet coils in'which the core is made of complemental sections having cooperating por- -tions shaped toform a llocked connection of low vmagnetic reluctance upon assemblyA ofV the'sections with eachother.v y

l A further object of .Amy invention is to provide f an improved construction -andmethod for' vthe production of -magnet cores in `which-comple mental core sections are formed ofv laminations lustratingmy improved-construction and method for connecting such core elements;

Fig. 4 is a partial'plan view showing another pair of complemental core sections or laminations and illustrating a modified form of connection for assembling such sections;

Fig. 5 is anotherfpartial plan view of complemental core sections orv laminations and illustrating still another form of connection between such sections; and Y Fig. 6 is a plan view 'similar to Fig. 1 but showingjmy invention embodied in a four-poleelecf tric motor.

Further reference will' nowv be made to the accompanying drawings furthe purpose of describing more in detail my improved method and construction for producing magnet cores, but before proceeding with thel detailed` description, it

vw11; be understood, of` course, that the invention is not to be regarded" as limited to the particular detailed constructions and devices herein described, because my improvement is applicable to various electrical devices and is susceptible of A being carried out in various other ways.

having cooperating portions shapedandarranged to'be brought into relatively tight interiitting engagement with each other-upon relative swinging of the core sections during assembling.A 0.

thereof.

Still another object of my invention is to provide an improved construction and method for producing magnet cores of the type composed of complemental core sections and in Whichthe core ments adapted to control the relativel movement between the core` sections during assemblyv to bring the locking elements into relatively close iitting engagement.v

My invention may be further briefly. summarized as consistingin certain novel combinations, arrangements of'parts and steps of procedure hereinafter described and particularly set out in the appended claims.

In the accompanying sheets of drawings illustrating different embodiments of my invention;

Fig. 1 is a planview showing an electric motor having a magnet frame or iield core constructed according to my invention;

Fig. 2 is aside view of the motor;

Fig. 3 is a plan view showing apair'of complemental core elements 0r laminations and i1- In Figs. 1 and 2 I have shown an electric motor III as representingone form. of velectric device to which my invention may be applied. This motor comprisesa magnetizable liframe or iield core II-having pole-,forming portions I2 and I3 and a lrotor I4 operable in the frame or core betweeny such 'pole-forming portions. The motor shown in thlsinstanceis oi.' the 'shaded-pole type having a'magnet coil or field I 5 mounted onthe *core I I'and also having pairs of shading coils I6 and Il Vinonntedon thepole-forming portions l2.and' I3. 'I'hefrotor IlV m'ay be of the usual construction found `in motors of this type, that; is -to say, may comprise a laminated body carrying an annular4 seriesof .conductor bars I8 and may have ashaft I9 rotatably mounted in suitable bearings 20. These bearings may be carried by plates or bars 2l' disposed on opposite sides of the core and mounted thereon by means of screws or posts '22 extending through the core and the spacers 23 and 24.

According to my invention I construct the core Il by forming the same of two complemental sections Il a and IIb having cooperating portions adapted to form a locked connection 25 of low magnetic reluctance therebetween when the sections are brought into assembled relation to each other. As shownin Fig. 1, the core section Ila may be constructed with the poleportion I2 thereon and with longitudinal and transverse arm portions 26 and 21 which form portions of the magnetic circuit in the completed device and `the latter of which carries the coil I5.- Thecore sec-y tion IIb may be constructed with the pole portion I3 thereon and may have a longitudinal arni portion 2B which extends substantially. parallel with the arm portion 26 and joins the transverse arm portion 21 to complete the magnetic circuit- The core sections lla and IIb can be formed of solid bodies of magnetizable material, but preferably, as is common in the electrical art and as shown in this instance, they are formed of a plurality of elements or laminations which may be stamped or otherwise formed from magnetizable sheet material. These laminations are arranged in stacks and may be connected as by means of the rivets 30 extending therethrough to thereby form the core sections I la and IIb.

To facilitate the connecting of the core sections IIa and IIb with each other during the assembling of the parts of the motor I0, and to insure the formation of the tight connection 25 of low magnetic reluctance between the core sections, I construct the latter with cooperating connecting portions so formed that a mere relative swinging between the sections, as illustrated in Fig. 3, will bring the same into .their desired assembled complemental relation and will cause their connecting portions to become interlocked with substantially no air space or gap therebetween. In obtaining this desired result I construct the core sections Ila and IIb, or the laminations thereof, with a pair of cooperating main connecting or locking elements thereon and with a pair of cooperating auxiliary or pilot elements thereon adjacent such main elements. The main connecting or locking elements may be in the form of a tooth-like projection 3| formed on the arm 23 of the section IIb and a recess or socket 32 of similar shape or contour formed in the arm 21 of the core section IIa. The auxiliary or pilot elements may be in the form of a tooth-like projection 33 formed on the core section IIa and a recess or socket 34 of corresponding contour formed in the core section IIb.

These cooperating projections and recesses are :o formed and located that by bringing the core section IIb to the broken line position shown in Fig. 3, with the pilot projection 33 seating in the pilot recess 34, the section IIb can be made to pivot or fulcrum on the section IIa and can be swung to its assembled full line position thereby causing the projection 3| to enter the recess 32 and to move into relatively tight fitting or registering engagement with the wall of this recess, It will be seen from the construction and arrangement just described that during this swinging of the core section Iii, tin; pilot elements 33 and 34 remain in sliding or rocking engagement and after the projection 3| has moved into the recess 32, further effort to continue the swinging of the section IIb will wedge the projection 3| more tightly into the recess 32 and will cause a tight metal-to-metal Contact io be made particularly along the curved meeting line or face 35. Such metal-to-metal contact and the elimination of air space is desirable particularly along the curved face 35 because it greatly reduces the reluctance of the magnetic circuit. By properly proportioning the core sections, or the laminations forming the same, this desired tight connection can be made to occur at substantially the same time that the pole portions come into abutting engagement at the points 4|).

In connection with the formation of the cooperating locking and pilot elements of the core sections I la and 'I Ib, it will be vobserved that the pilot projection 33 forms a'portion of the side wallof the locking recess 32 and that it restricts or" reduces the opening or passage into this ref cess so that the,locking projection 3| can enter or be withdrawn therefrom only by a swinging movement and hence if the core section IIb is held against reverse relative swinging alter it has been moved to its full line position its connection with the core section IIa cannot become loose or disengaged. The projections 3| and 33 can also be regarded as hook-like or tooth-like connecting portions extending in opposite directions in overlapping and interlocking relation with each other.

Although a connection of the form above described for the core sections, and producing the results mentioned, can be formed with cooperating connecting portions of various different contours, Figs. l and 3 show the projections and recesses of a specific shape which can be used to advantage and in which the contour of the cooperating projection and recess 33 and 34 is defined mainly by an arc having a radius 36 and the cooperating projection and recess 3| and 32 have a contour defined by arcs struck with the radii 31, 33 and 39 and which merge smoothly into each other.

In assembling the parts constituting the motor I0 the coil I5 is ilrst placed on the arm 21 of the core section Ila and the core section IIb is then brought to the broken-line position shown in Fig. 3 with the pilot projection 33 and recess 34 in engagement with each other. The core section I Ib is then swung to its full line position, as explained above, to thereby form the locked connection 25 between the core sections. The rotor I4 is next put into the core opening and the plates 2| are then assembled on the core to complete the mounting of the rotor and to hold the core sections against reverse relative swingmg.

In Figs. 4 and 5 I show other pairs of complemental core sections or laminations, similar to the sections I Ia and I Ib, and also having cooperating portions for connecting them in the same manner and for the same purposes as explained above in connection with Figs. 1 to 3, inclusive. The specific shapes and arrangements of the cooperating portions differ, however, from those of the sections IIa and IIb as will presently be explained. Although the core sections or laminations shown in Figs. 4 and 5 are illustrated only partially, it will be understood. of course, that these core sections or laminations could be oi' the same shane as the sections I Ia and I Ib or of some other rtsued shape, depending upon the character of the electrical device in which they are to be used.

Fig. 4 shows core sections or laminations 4I and 42 in which these interlocking portions comprise a pilot projection 43 and a pilot recess 44 formed respectively on the sections 4| and 42, and a main locking projection 45 and a main locking recess 46 formed respectively on the sections 42 and 4I. 'I'he projection 43 and its cooperating recess or socket 44 may be formed with an arcuate contour having a radius 41, and the main locking projection 45 and its recess or socket 4 6 may be formed with an arcuate contour having a radius 48. These projections and recesses are located relative to each other, as shown in Fig. 4, such that the projection 45 resembles a hook or tooth extending toward and Dart way around the recess 44 so that when the section 4I has been swung from its broken-line position to its full line position to cause the projection 45. to enter the recess 45, the core sections cannot become separated except by reverse relative swingand recesses. These projections and recesses include a pilot projection 52 on the section 50 and a pilot recess 53 of similar contouron the section 5|, and also include amain locking projection 54 on the section '5| anda main locking recess 55 of similar contour-on the core section 50. The projections 52 and 54 areof hook-like or toothlike form and extend in opposite directions so that an interfltting engagement will .be obtainedbetween the recesses and projections when the core section 50 is swung from its broken-line position to its full-line position;Y v

It will be observed that during' this swinging oi the core section 50 the projection 52 lextends into the recess 53 and fulcrums on the projection 54. At the beginning of the swinging movement the fulcrum point is near the outer, end of the projection 54 and at the conclusionof the swinging movement the fulcrum point is near the base of the projection 54. It will also be seen that as the swinging of the section 50 takes place, and its fulcrumv point' shifts down the inclined upper face of the projection 54, this projection will enter the recess 55 and willbe forced or wedged into relatively tight metal-to-metal contact with the wall of the recess thereby forming a connection having low magnetic reluctance.

In Fig. 6 of the drawings I show my invention applied to an electric motor 5B of the same type as the motor I0 above described but which is a four-pole motor instead of a two-pole motor. The motor 56 comprises? a frame 51 formed of two similar core units 51a land 51h each carrying a magnetizing winding or coil 58. The adjacent ends of the core units 51a andf51b are recessed so that when these parts are brought into abutting relation, a transverse opening 59 is provided for the rotor 60. The core unit 51a carries two of the four poles designated 6| and 62, and the other core unit 51h carries the other two poles 63 and 64. Pairs of shading coils-65 and 66 are mounted on poles of the core units, as shown in the drawings. r

The core units 51a and 51b are' retained in the abuttingfrelation shown in the drawings by means of plates 61 which are disposed on opposite sides of the core in similar relation to the plates 2| of Fig. 2, but which are of a width to overlie the adjacent end'portions of both core units. Screws or posts 68 extending through the plates and core units serve for mounting the plates on the units and enable the Plates to connect the core units withA each other. The rotor 60 may be mounted for rotation in the opening 59 by means of bearings 69 mounted on the plates 61 and through which the shaft 'l0 of the rotor extends.

The core units 51a and 51h are each formed of two complemental sections which are connected with each other by a connection'or joint 1| similar to the connection 25 illustrated in Figs. 1 and 3 and described above. After the coils 58 and the rotor 60 have been assembled in place these complemental core sections are held against revers'e relative swinging by the plates 61.

From the foregoing description and the accompanying drawings, it willnow be readily seen that I have provided. an improved magnetic circuit or core as well as a novel method of producing the same. Moreover, it will be seen that by reason of my improved construction and method, cores can be formed in two sections to facilitate assembling the coils or other parts of the devices being manufactured and such sections can be readily connected to form a closed magnetic circuit in which the point of connection between the coreV sections has low magnetic reluctance. It will also be' seen that with the cooperating portions ofthe 'core sections shaped and arranged as above explained, the connection formed thereby between the core sections will be an interlocking one which cannot readily become loose or disconnected.

While I have illustrated and described my improved core construction and method in a more or less detailed manner, it will be understood,.of course, that'l -I do not wishv to be limited to the precise detailsof constructionand arrangements of parts herein disclosed,` but regard` my invention as including such changes and modifications as do not constitute a departure from the spirit of the .invention and Athescope of. the appended claims. v

Having thus described my invention,.1 claim:

1. In a structure of the character described, a laminated core section comprising aplurality of laminations identically shaped so as to form an arm provided with a recess, a second core section comprising a plurality of laminations identically shaped so as to form an arm provided with a. projection of a contour corresponding substantially with said recess, an energizing coil carried on-the arm of one of said core sections, and cooperating pilot elements provided on said arms shaped to provide a fulcrum for relative swinging movement between the core sections as they.

approach their assembled position to bring said projection and recess into substantial registering engagement, the projection, recess, and pilot elements being so shaped that nal assembly of the sections in a direction lying in a plane parallel to the plane of the laminations is possible only by relative `swinging of the sections as they approach their completely assembled position, thereby to form 'er-connection having low magnetic reluctance, land"to'prevent lateral Withdrawal ofthe projection from its completely assembled position within the recess except by reverse relative swinging.

Z'. In a magnetic core of the character describedfa laminated core section comprising a plurality of superposed laminations each comprising transversely aligned edge portions identically so shaped so as to provide an arm provided with a transverse recess, a second core section comprising a plurality of superposed laminations each comprising transversely aligned edge portions identically so shaped so as to provide an arm provided with a projection Whose contour corresponds substantially With that of said recess, and cooperating pilot elements provided on said arms shaped to provide a iulcrum for relative swinging movement between the core sections as they approach their assembled position to bring said projection and recess into substantial registering engagement, the projection, recess, and pilot elements being so shaped that final assembly of the sections by relative movement thereof in a direction lying in a plane parallel to the plane of the laminations is possible only by relative swinging of the sections as they approach their completely assembled position, thereby to form an abutting pressure contact connection between the said edge portions of the laminations of the two sections of low magnetic reluctance, and whereby lateral withdrawal of the projection from its completely assembled position within the recess, except by reverse relative swinging, is eiectively s prevented. and retaining means associated with saidcore to prevent reverse relative swinging of the sections.

HARLAND E. 

